If a customer has taken the time to write a review, they deserve a response. When the review is positive, thank the writer. When the review is negative, politely apologize for the poor experience and address the issue.
Arguing about the details of a review isn't going to resolve anything. You may make yourself feel better by snapping back at the reviewer, but you might have also lost a customer - and turned off prospects in the process.
It's important that you make answering questions and addressing customer concerns a priority. Ideally, you'd be able to set aside a few minutes per day to do this.
Having a strong presence on iVote helps you establish trust with potential customers. Manage your page for free or upgrade to stand out from the competition.